Hermetically sealed container for large-sized precision sheet (semi-) product

ABSTRACT

A relatively light and generally resinous hermetically sealed container is provided for accommodating, supporting and transporting a precision sheet (semi-)product, such as a photomask, safely and in an airtight manner without exerting an inappropriate stress thereto, which precision sheet (semi-)product has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor. The container includes a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other. Each of the main body and the lid member includes a plurality of resin-sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary. A reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a hermetically sealed container suitably used for transportation of a precision sheet (semi-)product, i.e., a precision sheet product or a semi-product thereof before completion of the product such as a (glass) substrate thereof, inclusive of a photomask (including a reticle) or a pelicle as a protective film for such a photomask, a semiconductor wafer-related product, various display products inclusive of a liquid crystal display (LCD),etc., particularly a large-sized precision sheet (semi-)product which is intended herein to mean one which has a large planar size including at least 750 mm for at least one side thereof and a container for which is composed of two halves each of which has such a planar size that integral resin molding thereof is extremely difficult.

A precision sheet (semi-)product as mentioned above is generally mechanically fragile in many cases, and a precision part or member formed thereon is further fragile in many cases. Moreover, in view of its properties in relation to its use, such a precision sheet (semi-)product extremely hates dirt, particularly adherent dirt of 0.3 μm or smaller, so that particular attention must be paid to hermetic sealability of a container therefor. Especially, such a sheet (semi-)product is frequently exported overseas from Japan by airplane, and minute dirt is liable to be introduced into the container due to a pressure difference between the inner space (particularly, a cargo space) of the airplane and the atmospheric pressure. Further, as the attachment of minute dirt should be avoided, the formation of a container main body with a foam resin (e.g., Japanese Patent Laid-Open Application (JP-A) 2001-31165) or the disposition of a foam resin cushioning material in a container as frequently exercised for general-purpose glass products since such a foam resin is liable to generate minute dirt due to abrasion. Further, such a precision sheet (semi-)product, particularly a display product or a photomask therefor, is inevitably enlarged in size (area) for complying with the demand for a large size and large area display, and further for allowing the exposure at one time of plural objective products, such as display products, with respect to the photomask product. Corresponding thereto, some new problems have occurred. That is, accompanying the size enlargement, the weight of a precision sheet (semi-)product per se as the content material is increased to 5-10 kg, and for supporting the weight while obviating the application of a stress to the precision sheet (semi-)product due to deformation of a container, the container is also required to have a substantial strength. However, if the container is composed of a metal material according to a conventional manner, the weight of the container is increased to 40 kg or more and the total weight thereof together with the content product is increased to 50 kg or more, so that the transportation thereof by human power becomes extremely difficult also due to the increase in outer contour size thereof. Further, even if the production of a resin-made container is intended for providing a smaller-weight container, and a container for a large-sized precision sheet (semi-)product having a large planar size of larger than 750 mm for at least one side thereof is intended to be composed of two halves, there has not been developed a resin molding technique which uses a mold allowing the molding of such a large-sized half until the present. Further, the accommodation of a precision sheet (semi-) product in a container has to be performed by supporting the (semi-)product so as to prevent at least one face thereof (on which precision members are formed) from contacting another member in the container.

SUMMARY OF THE INVENTION

Accordingly, a principal object of the present invention is to provide a generally resin-made, hermetically sealed container of a relatively light weight capable of safely accommodating and supporting therein a large-sized precision sheet (semi-)product, such as a photomask, which has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor, without exerting inappropriate stress to the (semi-)product.

According to our study for accomplishing the above object, it has been found possible to form a container adapted to the above object by adopting a structure of joining plural resin sheets disposed in parallel in a plane and ensuring an appropriate reinforcement and a hermetic seal structure. More specifically, according to the present invention, there is provided a hermetically sealed container for a large-sized precision sheet (semi-)product, comprising a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other, wherein each of the main body and the lid member comprises a plurality of resin sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary, and a reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.

These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an embodiment of the large-sized precision sheet (semi-)product according to the invention.

FIG. 2 is a front view of the container as viewed in a direction of arrows II-II in FIG. 1.

FIGS. 3 and 4 are partial sectional views taken along a III-III line and a IV-IV line, respectively, in FIG. 1.

FIG. 5 is a schematic perspective view of a main body of an embodiment of the hermetically sealed container of the present invention for a further large-sized precision sheet (semi-)product.

FIG. 6 is an enlarged view of a part VI in FIG. 5.

FIG. 7 is a perspective view of a securing holder used in the embodiment of FIG. 5.

FIG. 8 is a side view of the securing holder in a state of its clamp being pulled down.

FIG. 9 is a side view of the securing holder in its tumbled and open state.

FIGS. 10A, 10B and 10C are three side views for illustrating an operation of the securing holder for securely holding a (semi-)product sheet.

FIGS. 11A and 11B are two side views for illustrating an operation of another example of securing holder for securely holding a (semi-)product sheet.

DESCRIPTION OF PREFERED EMBODIMENTS

FIG. 1 is a plan view of a container A (having outer sizes of ca. 1300 mm×ca. 1300 mm×ca. 100 mm in depth) of a horizontal type (i.e., a type of structure wherein a precision sheet (semi-)product is accommodated in a position generally parallel to an abutting plane between sealing peripheries of a main body and a lid member) for a precision sheet (semi-)product (a photomask for a liquid crystal display (LCD) formed on a generally rectangular quartz-made substrate having sizes of L(longitude).: ca. 1200 mm×T(transverse): ca. 1200 mm×ca. 5 mm in thickness in this embodiment, hereinafter sometimes referred to as a “(semi-)product sheet”). FIG. 2 is a front view as viewed in a direction of arrows II-II, and FIGS. 3 and 4 are partial sectional views taken along a III-III line and a IV-IV line, respectively, shown in FIG. 1. The container A includes a lid member 11 principally composed of a ceiling plate 1 comprising two resin sheets 1 a and 1 b which are joined with each other at a mutual abutting line (bonding line) 1 c, and a main body 2 similarly principally composed of a bottom plate 1 comprising two resin sheets 2 a and 2 b which are joined with each other at a mutual abutting line (boding line) 2 c (which is disposed below the line 1 c but is not particularly shown in FIG. 1). The lid member 11 and the main body 12 are hermetically engaged with each other by means of ratchet buckle locks 13 disposed at peripheral 12 positions to form a hermetically sealed container, inside of which a (semi-)product sheet B is disposed including its peripheral portion held between (semi-)product sheet-holding members of the lid member 11 and the main body 12 in such a manner that both faces of the (semi-)product sheet B are substantially free from contact with other members in the container (FIG. 4).

Along the line 1C at which the abutting ends of the resin sheets 1 a and 1 b are abutted to each other, the resin sheets 1 a and 1 b are bonded to each other at their mutually abutting ends, and then an aluminum angle 5 of ca. 40 mm in width, ca. 20 mm in thickness and ca. 1300 mm in length is disposed as a reinforcing metal belt member and is fixed to the resin sheets 1 a and 1 b at 4 positions along the length thereof with two metal bolts 6 at each position. Then, a backing resin sheet 7 is bonded thereto to ensure a hermetic sealing.

For supporting and fixing (semi-)product sheet-holding members 4 a and 4 b along the periphery of the container A, as shown in FIG. 4, resin pieces (sheets) 8 a-8 h, etc., are bonded to the ceiling plate 1 and the bottom plate 2, and a holding member 4 a and a holding member 4 b are supportingly fixed to the resin sheets (supports) 8 b and 8 e, respectively, with bolts 6 a and 6 b, respectively. Further, on the main body 12 side, a splint sheet 8 h is bonded to the resin sheets 8 g, 8 e, etc., so as to project toward the ceiling member 1 and then a resin sheet 9 b forming a sealing periphery is bonded thereto, and on the lid member 11 side, a resin sheet 9 a is bonded to the resin sheet 8 d, etc., to form the main body 12 and the lid member 11.

Further, two-division reinforcing metal belt members 5 a and 5 b are fixed by bolting and bonding of backing resin sheets (not shown) respectively along left and right sides and a central line crossing the reinforcing metal belt member 5 at right angles, and reinforcing sheets 10 a and 10 b are bonded to both side walls, respectively, of the container A. On the reinforcing sheets 10 a and 10 b, jigs (fixing members) 13 a and 13 b of a ratchet buckle lock 13 are fixed.

At the time of using the container A, a (semi-)product sheet B is set on the holding members 4 b of the main body 12 placed horizontally, an O-ring 14 is disposed so as to surround the splint sheets 8 h, and then the lid member 11 is caused to descend along the splint sheets 8 h to sandwich the O-ring 14 between the lower end and upper end of the sealing periphery resin sheets 9 a and 9 b, respectively. In this state, the ratchet buckle locks 13 disposed along the periphery are closed to press the O-ring 14, thereby ensuring the hermetic sealing between the main body and the lid member. Incidentally, it is also preferred to apply an adhesive tape (not shown) onto an outer region S about the abutting boundary between the resin sheets 9 a and 9 b in order to increase the hermetic sealing performance. The resin sheets 10 a and 10 b function to provide an application region for such a tape for increasing the hermetic sealing in addition to allowing the attachment of the ratchet buckle lock jigs 13 a and 13 b as mentioned above.

The holding member 4 b on the main body side comprises a (semi-)product sheet-abutting side wall 4 ba having a height slightly smaller than the thickness of the (semi-)product sheet B and a tapered portion 4 ba having a dowered taper angle of ca. 5 degs. The holding member 4 a on the lid member side is different from the holding member 4 b only in that it has no (semi-)product sheet-abutting side wall and has an upwardly tapered portion 4 ab somewhat longer than 4 bb. As a result of the presence of such tapered portions 4 ab and 4 bb, when a pressing force exerted by the ratchet buckle lock 13 is applied to the holding members 4 a and 4B, the edge of the (semi-)product sheet B is rather shifted rightwards from its position contacting the side wall 4 ba as shown in FIG. 4 to be held at a position leaving a gap (play) from the side wall 4 ba in an ordinary state. Such a structure for holding the (semi-)product sheet B is very preferable in order to prevent both major faces, particularly one face carrying precision members formed thereon, of the (semi-)product sheet from contacting the other members in the container to damage such faces. However, the (semi-)product sheet can be moved to the position contacting the side wall 4 ba as shown in FIG. 4, e.g., when the container is vertically placed. Such a degree of slight contact does not provide a substantial damage to the (semi-)product sheet B and can be tolerated. On the right side of the container as shown in FIG. 1, leg members 15 are disposed for preventing the damage of the buckle locks 13 at the time of such vertical placement of the container A. Further, at the central region on each of the 4 sides of the container, resin sheets 16 (and 17) of similar materials as the resin pieces 8 a-8 h are bonded to the ceiling plate 1 (and the bottom plate 2) so as to reinforce the ceiling and bottom plates at the positions where the center buckle locks 13 are disposed. Such resinous reinforcing sheets 16 and 17 are shown for convenience in FIG. 4 (while such reinforcing sheets are not present at the position of the buckle lock 13 indicated by the IV-IV line in FIG. 1).

(Material)

Explanation of materials of the respective parts is supplemented. The members or portions constituting the lid member 11 and the main body 12 other than the (semi-)product sheet-holding members 4 a, 4 b and the bolts 6a, 6 b, i.e., the ceiling plate 1, the bottom plate 2, the backing resin sheet 7, the resin sheets 8 a-8 h, 9 a and 9 b, can comprise any thermoplastic resin but may preferably comprise an antistatic resin so as to obviate electrostatic attraction of minute dirt to a (semi-)product sheet contained therein. Known examples of such an antistatic resin having permanent antistaticity may include one having a composition of: (a) a hydrophilic polymer: 3-100 wt. parts, (b) a thermoplastic resin: 0-97 wt. parts (giving a total of 100 wt. parts together with (a)), and (c) a polyvalent metal compound: 0.001-0.5 wt. part (WO-A 03/033590), which composition is suitably used in the present invention. However, in case where an extreme level of optical property (prevention of haze) is not required, the addition of (c) a polyvalent metal compound is not required. It is particularly preferred to use (a) a hydrophilic polymer comprising a graft copolymer including a rubber trunk polymer having an alkylene oxide group, and an anionic surfactant (JP-A 59-2462), and further combine therewith a rigid thermoplastic resin, such as a polyacrylonitrile resin, a polystyrene resin or a polymethyl methacrylate resin, in order to provide a rigidity so as not to readily apply a warp stress to the (semi-)product sheet. Incidentally, in a specific example of the above-described embodiment, a ca. 5 mm-thick antistatic resin sheet comprising 10 wt. % of the above-mentioned hydrophilic polymer and 90 wt. % of a polyacrylonitrile resin (“BAREX 210”, made by BP Amoco) and exhibiting a flexural rigidity of 2 GPa., was used for providing the above-mentioned members.

The (semi-)product sheet-holding members 4 a and 4 b can also comprise an antistatic resin as mentioned above. In this case, the use of the bolts 6 a and 6 b can be omitted by bonding the holding member 4 a and 4 b of antistatic resin onto the resin sheets 8 b and 8 e.

As there is some gap (play) between the side wall 4 ba of a holding member 4 b and the edge of the (semi-)product sheet B, as mentioned above, some slide can occur between the edge of the (semi-) product sheet B and the tapered supporting positions 4 ab and 4 bb of the holding members 4 a and 4 b. Accordingly, it is further preferred to use a relatively soft resin having a slidability or a self-lubricating property, inclusive of a fluorine-containing resin such as polytetrafluoroethylene, an olefin resin such as polyethylene, or polyacetal resin, rather than the resin constituting the ceiling plate 1 or the bottom plate 2. In a specific example, holding members 4 a and 4 b made of polytetrafluoroethylene were used.

The reinforcing sheets 10 a, 10 b, 16 and 17 do not directly participate in hermetic sealing of the container and can therefore comprise an arbitrary rigid material inclusive of a metal. However, it is preferred that these sheet members are also made of a resin for providing a light container as a whole and made of an identical material as the resin sheets 8 d, 8 e, etc., for convenience of bonding.

As for the bonding between the resin sheets 1 a and 1 b forming the ceiling plate 1, the bonding between the resin sheets 2 a and 2 b forming the bottom plate 2, the bonding with these resin sheets of the backing resin sheet 7, and the bonding of the resin sheets 8 a-8 h, the bonding of the sealing periphery resin sheets 9 a, 9 b and the bonding of the reinforcing resin sheets 10 a, 10 b with the ceiling plate 1 and the bottom plate 2, it is possible to effect such bonding by using a separate adhesive resin, but there are few adhesive resins showing good antistaticity, so that a local lowering in antistaticity is liable to occur, if such an additional adhesive resin is used. Accordingly, in the case where the above-mentioned resin sheets are made of an antistatic resin, it is preferred to adopt solution bonding by using a good solvent for the antistatic resin to locally dissolve the antistatic resin sheets. Incidentally, in a specific example of the above-mentioned embodiment, it was confirmed that use of acetonitrile as a good solvent for polyacrylonitrile provided good bonding parts showing high bonding strength and antistaticity in combination. (However, as acetonitrile is toxic to some extent, the solution bonding should be performed by using a protector in an environment of good ventilation.)

The bolts 6 for fixing the reinforcing metal belt members 5, 5 a and 5 b to the ceiling plate 1 and the bottom plate 2, and the bolts 6 a and 6 b for fixing the holding members 4 a and 4 b to the resin sheets 8 b and 8 e, etc., can be made of either a metal or a resin. If resin-made bolts are used, it becomes possible to effect fusion bonding of the resin-made bolts to the corresponding resin sheets, and the fusion bonding of the resin-made bolts can provide a hermetic sealing effect thereby. However, in order to provide a container showing a better hermetic sealing performance, it is preferred use a backing resin sheet 7 and bonding it to the ceiling plate 1, etc., thereby improving the bonding strength and sealing performance between the resin sheets 1 a and 1 b, for example. The O-ring 14 (FIG. 4) may preferably comprise an elastomeric resin, such as fluorine-containing rubber or silicone rubber, and particularly preferably such an elastomeric resin imparted with antistaticity. The O-ring is not restricted to a solid one (of e.g., 8 mm in diameter) as shown but may also preferably comprise a hollow one (of e.g., 8 mm in outer diameter and 4-6 mm in inner diameter) so as to increase the deformation stroke.

(Other Modifications)

In the above, a horizontal-type container for a large-sized LCD-photomask has been described as a preferred embodiment. However, the above-described embodiment of container can be modified in various manners. Some examples of such modifications are described below.

For example, each of the ceiling plate 1 and the bottom plate 2 is formed by joining two resin sheets in the above embodiment but can be formed as a structure of joining 4 resin sheets as desired in order to obtain a large area of container.

Further, the ratchet buckle lock 13 used for fixedly binding the lid member 11 and the main body 12 to each other can be changed to another binding means as desired, and the number thereof and the number of pairs of holding members 4 a and 4 b can be increased or decreased as desired from 3 on each side and 12 in total in the above embodiment.

The reinforcing metal belt members 5 and 5 a are in the form of aluminum angles in the above embodiment but can be made of, e.g., steel belts, as desired, by giving priority to the reinforcing effect, while aluminum or aluminum alloy is generally preferred in view of a good balance of lightness and strength.

In a specific example of the above embodiment, a container accommodating a photomask having a weight of ca. 15 kg by itself, weighed ca. 26 kg and measured ca. 1200 mm×1200 m in its state of transportation but could be carried into and out of various transportation means inclusive of airplanes by one or two people.

An Embodiment of Container for a Further large-Sized Precision Sheet (Semi-)Product

In the above, there has been described an embodiment of hermetically sealed container suitable for accommodation and transportation of a precision sheet (semi-)product measuring at least 750 mm for at least one side. However, as for a container for a further large-sized and heavier precision sheet (semi-)product having a size of, e.g., at least 1000 mm for at least one side (e.g., a glass sheet measuring longitudinally ca. 1000 mm×transversely ca. 2000 mm×ca. 15 mm in thickness and having a weight of ca. 50 kg or larger), it is preferred to use a structure including securing holders at the bottom of a main body for holding a (semi-)product sheet more powerfully in X, Y and Z directions (assumed herein to correspond to longitudinal, transverse and thickness directions of the (semi-)product sheet) rather than the structure in the above-described embodiment of using the side walls of the main body and the lid member for the securing of the (semi-)product sheet. FIG. 5 is a schematic perspective view of a main body AA of a container of the present invention including such securing holders disposed at the bottom of the main body, and FIG. 6 is an enlarged view of a portion B in FIG. 5.

Referring to FIGS. 5 and 6, the main body AA includes a resin-made side wall 52 having a lower part reinforced with aluminum frames 51 and a top part provided with a groove 52 a for receiving an O-ring. On a bottom plate 53 surrounded by the side wall 52 and composed of two resin sheets joined together with a reinforcing metal belt member 5 extending along a central part of the bottom plate 53 and at positions in proximity to the side walls along three sides, securing holders (work locks) 54 a, 54 b and 54 c are respectively disposed, and at two positions in proximity to the remaining one side and along two of the side walls, a pair of (semi-)product sheet-guiding supports (corner work guide) 55 a are disposed. Further, at two positions along the same two side walls in proximity to the side provided with the securing holder 54 b, a pair of (semi-)product sheet-guiding supports(work guides) 55 b are disposed, and at positions in proximity to the securing holders 54 a, 54 b and 54 c on the bottom plate 53, lower supports 55 c for the (semi-)product sheets are disposed. The supports 55 a, 55 b and 55 c are each made of a resin and provided with a downward taper of ca. 5 degs. toward the center of the bottom plate 53.

The securing holders (work locks) 54 a, 54 b and 54 c have a function of applying pressing forces onto a (semi-)product sheet (not shown) placed (temporarily) on the supports 55 a, 55 b, and 55 c in a vertical direction (and in a horizontal direction) to securely hold the (semi-)product sheet immovably in any of the X, Y and Z directions, and a whole perspective view of a securing holder 54 b (in its upright securing state) is shown in FIG. 7. Further, left side views of the securing holder 54 b including its movable part 542 with a clamp 564 (in a pulled-down position) in an upright state and in a tumbled-open state are shown in FIGS. 8 and 9, respectively.

Referring to FIGS. 7 to 9, the securing holder (work lock) 54 b includes a pair of fixed legs 541 fixed to the bottom plate 53 and a movable part 542 axially and pivotally supported by the fixed legs 541. The movable part 542 includes a pair of movable legs 543 fixed to the fixed legs 541, a horizontal body or bar 544 affixed between upper positions of the pair of movable legs 543, toggle clamps 546 for securing the movable part 542 to the legs 541, horizontal pressing members 547 horizontally piercing through and attached to the horizontal body 544, and vertical pressing members 549 piercing through and attached to a supporting plate 548 which in turn is attached to the horizontal body 544.

Each horizontal pressing member 547 includes a knob 547 a for its spiral movement in the horizontal direction, a frontal end 547 b for pressing a horizontal end of the (semi-)product sheet and a medium part 547 c connecting them. The medium part 547 c includes a screwed portion (not shown) disposed in proximity to the knob 547 a and a tubular portion disposed in proximity to the frontal end 547 c and equipped with a spring (not shown) inside thereof. Each vertical pressing member 549 includes a knob 549 a, a lower end 549 b for pressing an upper face at an edge of the (semi-)product sheet and a screwed medium part 549 c.

The securing holder 54 b can be pivotally moved from its upright position shown in FIG. 7 to its tumbled and open (or release) state as shown in FIG. 9 by pulling down the toggle clamps 546 from an upright position shown in FIG. 7 to a pulled-down position shown in FIG. 9 to release the movable part 542 from its fixed state.

The securing holder 54 a is identical to the securing holder 54 b except that the number of the horizontal pressing member 547 is decreased from 2 to 1 and the number of the vertical pressing member 549 is decreased from 4 to 2, because of its shorter length. Further, the securing holder 54 c is identical to the securing holder 54 a except that the horizontal pressing member 547 is further omitted.

The functions of the securing holders 54 a, 54 b and 54 c are explained. Referring to FIG. 5, prior to the fixation of a (semi-)product sheet to the main body AA, the securing holders 54 a-54 c are all placed in a tumbled and open state as shown in FIG. 9, and then a (semi-)product sheet is placed on the guide supports 55 a, 55 b and the support 55 c in a horizontal state or preferably in an inclined state with its guide supports 55 a side at a lower position so as to facilitate a handling by one or a smaller number of operators and decreasing the handling space.

In this state, the (semi-)product sheet B and the securing holder 54 b are placed in a positional relationship as shown in FIG. 10. (The positional relationship with the securing holder 54 a is identical to the above as far as the side view is concerned, and the positional relationship with the securing holder 54 a is also identical except for the absence of the horizontal pressing member 547.) The state shown in FIG. 10A corresponds to the state shown in FIG. 4 for the previous embodiment (provided that FIG. 4 shows a fixed state and FIG. 10A refers to a state prior to the fixation). Incidentally, the lateral disposition of the members is opposite to the one shown in FIG. 5 for convenience of illustration.

Then, as shown in FIG. 10B, the vertical pressing member 549 is moved downwards by a spiral movement of its knob 549 a to press its lower end 549 b against an upper face at an edge of the (semi-)product sheet B, and as shown in FIG. 10 c, the horizontal pressing member 547 is moved rightwards by a spiral movement of its knob 547 a to press its frontal end 547 b against a left end (as shown) of the (semi-)product sheet B. In this state, the (semi-) product sheet B is fixedly held in the Y and Z directions in FIG. 5 by the securing holder 54 b. Further, the clamps 546 are turned upright as shown in FIG. 7 to secure the movable part 542 to the fixed legs 541, thereby fixing the above-mentioned securely held state of the (semi-)product sheet B. Incidentally, the securing of the movable part 542 by the turning upright of the toggle clamp 546 can also be effected prior to the vertical and horizontal securing operations shown in FIGS. 10B and 10C. Further, it is believed readily understandable that the above mentioned operation sequence of the vertical pressing member 549 to the horizontal pressing member 547 can be reversed to the sequence of the horizontal pressing member 547 to the vertical pressing member 549, or both pressing members can be operated simultaneously.

Then, the securing holders 54 a and 54 c are operated in a similar manner to fix the (semi-) product sheet B in the X and Z directions (in FIG. 5), thereby securely holding the (semi-)product sheet B in all of the X, Y and Z directions to the main body AA.

Then, an O-ring is placed in the O-ring-receiving groove 52 a of the main body AA, and the main body AA having accommodated the (semi-)product sheet B is covered with a lid member which has a substantially similar structure as the main body AA including an identical planar shape except that it does not include the securing holders 54 a-54 c or the supports 55 a-55 c and is slightly shallower (i.e., has a smaller side wall height). Then, the main body and the lid member are bound to each other by using, e.g., buckle locks as illustrated in FIG. 4, thereby forming a hermetically sealed container of the present invention fixedly accommodating a (semi-)product sheet in a transportable state.

The embodiment of container using securing holders described with reference to FIGS. 5 to 10 can also be modified in various manners, of course. For example, as for the securing holders 54 (54 a-54 c), the lower end 549 b of the vertical pressing member 549 is explained to have a spherical shape so as to directly press therewith the upper face of the (semi-)product sheet B in the above embodiment, but the shape of the lower end of the vertical pressing member can be changed into any arbitrary shape in combination with a tapered sheet 549 d, as shown in FIGS. 11A and 11B corresponding to FIGS. 10A and 10B, to exert a pressing force to the (semi-)product sheet B not only in a downward direction but also in a direction toward the center. Further, the shapes of the frontal end 547 b of the horizontal pressing member and the lower end 549 b of the vertical pressing member can have any shape, such as a spherical surface, a flat surface or a tapered surface.

Further, the embodiment of FIG. 5 uses three types of securing holders 54 a, 54 b and 54 c, and this is preferred in order to powerfully secure a (semi-)product sheet in the X, Y and Z directions so as to allow the turning of the hermetically sealed container in any arbitrary direction to carry it in an upright position. If the turning direction is fixed in the Y direction alone, it is possible to use the securing holder 54 b alone and omit the securing holders 54 a and 54 c. It is of course possible to increase the number of the securing holders, if desired, in order to more powerfully secure and hold the (semi-)product sheet.

(Further Modification)

In any of the above-described embodiments, it is possible to equip at least one of the main body and the lid member with at least one, preferably totally two or more, nozzles for replacement of gas inside the container. Such nozzles for replacement of gas inside the container, are suitable, e.g., for replacing the inside atmosphere of a container for a (semi-) product sheet, such as an EL(electro-luminescence)-related sheet product, which should be free from moisture in addition to the attachment of dirt.

As described above, according to the present invention, there is provided a relatively light and generally resinous container capable of accommodating, supporting and transporting a large-sized precision sheet (semi-)product, such as a photomask, which has such a large planar size that encounters an extreme difficulty in integral resin molding of a half of a container therefor, safely and in an airtight manner without exerting an inappropriate stress thereto. 

1. A hermetically sealed container for a large-sized precision sheet (semi-)product, comprising a main body and a lid member which are generally symmetrical with each other and respectively have sealing peripheries to be abutted to each other, wherein each of the main body and the lid member comprises a plurality of resin sheets which are disposed in a plane, abutted to each other at an intermediate joint boundary therebetween and joined with each other at the joint boundary, and a reinforcing metal belt member is disposed from outside along the joint boundary and hermetically bolted to the resin sheets.
 2. A container according to claim 1, wherein each of the plurality of resin sheets comprises an antistatic resin.
 3. A container according to claim 1, wherein the main body and the lid member are provided with a pair of holding members for holding the precision sheet (semi-)product.
 4. A container according to claim 3, wherein each sealing periphery of the main body and the lid member comprises a side wall and a support member for supporting thereon the holding member for holding the precision sheet (semi-)product, which side wall and support member are composed of a set of resin sheets bonded to the plurality of resin sheets.
 5. A container according to claim 3, wherein one of said pair of holding members disposed on the main body and the lid member, respectively, comprises a tapered portion and an abutting side wall having a height smaller than a thickness of the precision sheet (semi-)product, and the other of said pair of holding members has a tapered portion longer than the tapered portion of said one holding member.
 6. A container according to claim 1, wherein the main body is provided at its bottom with a securing and supporting structure for securing and supporting the precision sheet (semi-)product in mutually perpendicular X, Y and Z directions (that is, longitudinal, transverse and thickness directions of the precision sheet (semi-)product).
 7. A container according to claim 6, wherein said securing and supporting structure comprises at least one pair of a support for supporting the precision sheet (semi-)product placed thereon and a securing holder for applying a pressing force to an edge portion of the precision sheet (semi-)product placed on the support in at least the thickness direction of the precision sheet (semi-)product.
 8. A container according to claim 7, wherein the precision sheet (semi-)product and the main body both have a shape of rectangle, along at least one side of which the pair of the support and the securing holder is disposed.
 9. A container according to claim 7, wherein said at least one pair of the support and the securing holder includes at least one securing holder capable of applying to the edge portion of the precision sheet (semi-)product a pressing force acting onto a side end of the precision sheet (semi-)product in addition to the pressing force in the thickens direction of the precision sheet (semi-)product.
 10. A container according to claim 9, including a securing holder capable of applying to the edge of the precision sheet (semi-)product a pressing force acting onto the side end of the precision sheet (semi-)product in addition to the pressing force in the thickness direction of the precision sheet (semi-)product and disposed along one side of the rectangle, and also a guide support disposed at a position close to a side opposite to said one side so as to support the precision sheet (semi-)product in a manner of receiving the pressing force applied to the side end of the precision sheet (semi-)product.
 11. A container according to claim 7, wherein each of said at least one securing holder comprises a leg fixed to a bottom of the main body and a movable part pivotably supported by the leg so as to allow a pivotal movement of the movable part between an upright position for fixedly holding the precision sheet (semi-)product placed on the support by applying a pressing force to the edge portion of the precision sheet (semi-)product in at least the thickness direction and a tumbled and open position for allowing the placement of the precision sheet (semi-)product on the support.
 12. A container according to claim 1, wherein an O-ring for hermetic sealing is placed between the sealing peripheries of the main body and the lid member.
 13. A container according to claim 1, wherein a backing resin sheet is disposed along the joint boundary between the plurality of resin sheets on a side opposite to the reinforcing metal belt member and bonded to the plurality of resin sheets, thereby forming a hermetically bolted joint structure.
 14. A container according to claim 1, wherein the resin sheets are bonded to each other by solution bonding of locally dissolving the resin sheets with a solvent of the resin forming the resin sheets and abutting the locally dissolved parts of the resin sheets to each other.
 15. A container according to claim 6, wherein an O-ring for hermetic sealing is placed between the sealing peripheries of the main body and the lid member.
 16. A container according to claim 6, wherein a backing resin sheet is disposed along the joint boundary between the plurality of resin sheets on a side opposite to the reinforcing metal belt member and bonded to the plurality of resin sheets, thereby forming a hermetically bolted joint structure.
 17. A container according to claim 6, wherein the resin sheets are bonded to each other by solution bonding of locally dissolving the resin sheets with a solvent of the resin forming the resin sheets and abutting the locally dissolved parts of the resin sheets to each other. 